🧪 Assignment Title: “Prokaryotes in Action: Clinical Bacterial ID and Classification”
📌 Purpose
This activity will help you apply your understanding of prokaryotic cell structure, Gram staining, and bacterial identification to real-world clinical and environmental scenarios. By classifying bacteria using key characteristics, you’ll strengthen your ability to analyze unknown samples and connect microbial traits to diagnosis and treatment.
🎯 Learning Outcomes
After completing this assignment, you should be able to:
- Distinguish between major types of prokaryotic organisms using cell wall, morphology, and metabolic characteristics.
- Use bacterial classification tools (e.g., dichotomous keys, flowcharts) to hypothesize identity of unknown organisms.
- Describe how bacterial traits impact medical diagnosis and treatment decisions.
📝 Instructions & Tasks
🔍 Step 1: Case-Based Bacterial Identification (Choose 1 of 2 cases)
Read one of the two short case studies below and use your knowledge of bacterial cell structures and Gram staining to predict the bacterial identity.
Case Study 1 – Skin Infection A 14-year-old football player has a swollen, red lesion on his thigh after practice. The doctor takes a sample and performs a Gram stain. The results show Gram-positive cocci in clusters. The patient has a fever and mild pain at the site.
What are likely bacterial candidates? What additional tests might confirm the diagnosis? Is the bacteria aerobic or anaerobic? Why does this information matter for treatment?
Case Study 2 – Foodborne Illness A 35-year-old woman visits the ER with severe abdominal cramps and bloody diarrhea after eating a rare hamburger. The lab identifies Gram-negative bacilli and notes the bacteria ferments lactose and produces a shiga-like toxin.
What bacterial group could this be? What common species might fit this description? What structural features or virulence factors contribute to the symptoms?
Respond in 1–2 well-organized paragraphs for your chosen case.
🧠 Step 2: Bacterial ID Flowchart (Hands-On Practice)
Use the simple bacterial identification flowchart provided below (or one from class) to classify 3 fictional bacteria based on the provided traits.
Organism A:
- Gram-positive cocci
- Catalase-positive
- Facultative anaerobe
Organism B:
- Gram-negative rod
- Oxidase-negative
- Glucose fermenter
Organism C:
- Acid-fast rod
- Obligate aerobe
Complete the ID for each and list a real-world organism that fits the description (e.g., Staphylococcus aureus, E. coli, etc.)
🔬 Step 3: Compare Archaea and Bacteria
Create a comparison chart or table showing at least 4 differences between bacteria and archaea. Include features such as:
- Cell wall structure
- Membrane lipids
- Habitat
- Sensitivity to antibiotics
- Ribosomal structure
- Ability to Gram stain